Question

Fruit colour in squash is an example of ___________
A. Dominant epistasis
B. Complementary genes
C. Inhibitory genes
D. Recessive epistasis

Answer 1

Hint: Genetic pool remains constant but sometimes there occur mutations. These changes in the genes bring the phenotypic or genotypic changes. The gene alteration can be in either way. The suppression of itself or the other gene is one way.

Complete answer:
Fruit and flowers have colours which are due to the genes present in them. The dominant allele will express its colour. Heterozygous parents mean having two different alleles for a single trait.
Epistasis is an interaction of genes, not the alleles. In this condition, a gene‘s expression is suppressed by the other.

Let us see the terms in the question.
> Option A: Dominant epistasis: When one allele of a gene can mask the alleles of the other. The inheritance of one or more copies of this dominant allele, they will have this trait. It happens when the parents are heterozygous. For example- IN squash the colour may be yellow, green etc., yellow (Aa, AA) is dominant over green (aa). As in this, the dominant epistasis occurs, this gene will be affected by some other gene B. this b gene will be the bully gene masking the expression of gene A.

> Option B: Complementary genes: When both genes contribute to a single character, they both cover the effect of each other are the complementary genes. In simpler words, when both the dominant characters are required to make the dominant characteristic.

> Option C: Inhibitory genes: A gene which will inhibit the other active allele in different locus is called an inhibitory gene. One inhibitory gene will suppress the expression of the other dominant gene.

> Option D: Recessive epistasis: When the recessive allele of one gene will suppress the expression of the alleles from the other genes, it is called recessive epistasis.

Hence, The correct answer is option (A).

Note: Epistasis is the effect of a mutation in a gene. Mutation depends on the genetic background in which it is occurring. It is the outcome of how the genetic elements alleles interact with each other. They are important for evolutionary pathways.